Those who perform at a high-level and consistently seems to enjoy what they do, when they were asked.
No, they do not necessarily see what they do as a passion. Rather, their performance seems to be driven by the will of wanting to be good at a something.
Also, they do not necessarily enjoy every single aspect of what they do.
Professionals practice their craft daily, and every craft has some element of drudgery involved that the professional must deal with daily.
It is not always fun and game.
But those professionals see past the drudgery and strive to be immersed and at their best every single moment.
While they strive to be their best, they express the care by paying attention to details and learning from the performance.
If it must be done, I see to it because I care about how it gets done.
For those who excel, performance, enjoyment, and even more so, the sense of care and learning all seem to feed off one another.